The project objective is to develop sub-sea NDT techniques to be applied by novel robots developed to be deployed to sub-sea structures by a Remote Operating Vehicle (ROV) for the examination of critical welds and lengths of sub-sea pipelines. The NDT techniques, systems and sensors to be developed for sub-sea ROV deployed applications include: 1. Phased Array Automated Ultrasonic Testing (PA - AUT) for the volumetric examination of critical sub-sea jacket welds on structural tubulars, support legs and node sections 2. Alternating Current Field Measurement (ACFM) for the surface and near surface examination of critical sub-sea jacket welds on structural tubulars, support legs and node sections 3. Long Range Ultrasonic Testing (LRUT) using guided ultrasonic waves for the examination of sub-sea flow lines, oil & gas import and export lines and risers for corrosion and other volumetric defects. Although the above are recognised established NDT techniques, their application to offshore sub-sea structures by ROVs has yet to be developed and constitutes a significant challenge. The use of ROV deployed NDT techniques is now preferred to those applied by divers because of personal safety and dive depth limitations. In the North Sea there are about 150 fixed platforms and over 60% of them are older than 20 years and beyond their original design life. The need for this work to be undertaken comes from the concerns by national and European regulatory bodies as to the condition of such structures. It is likely that further life extension of these platforms and an increase in technical duty (e.g. tie ins to other oil and gas fields)